Self-propelled wheel chair and steering control therefor



July 5, 1955 w. H. FULTON ET AL SELF-PROPELLED WHEEL CHAIR AND STEERING CONTROL TI-IEREFORy 5 Sheets-Sheet l Filed Aug.

IN V EN TORS R. NJ, S R m0 U w N FM R .L m HE TI C A MN AE IR MA W July 5, 1955 w. H. FULTON ET AL 2,712,357

TROL THEREF'OR SELF-PROPELLED WHEEL CHAIR AND STEERING CON 3 Sheets-Sheet 2 Filed Aug. 4, 1955 MOOR,JR.

INVENTORS WILLIAM H. FULTON BY ARENC ATTORNEYS July 5, 1955 SELF-PROPELLED Filed Aug. 4, 1955 w. H. FULTON ETAL 2,712,357 WHEEL CHAIR AND STEERING CONTROL THEREFOR 3 Sheets-Sheet 5 Fig. 4

Fig.5

INVENTORS WILLIAM H, FULTON ARENC ATTORNEYS 4located for operation by the United States Patent @ffice SELF-PROPELLED WHEEL CHAR AND STEERING CONTROL THEREFOR William H. Fulton, Chelmsford, Mass., and Clarence L. Moor, Jr., Laconia, N. H.; said Fulton assigner to said Moor Application August 4, 1953, Serial No. 372,289 S Claims. (Cl. 13d-6.28)

This invention relates to a self-propelled wheel chair or the like conveyance used by crippled or handicapped persons, and its principal objects are to provide a conveyance which may be used both indoors and outdoors and which may operate over uneven terrain, such as curbings and wide, low steps that often provide the approach to public buildings, and to provide a reliable, eicient and safe convey-ance which may be readily operated by a single control which may be actuated by any controllable muscle of a handicapped person, which respond quickly to the manipulations of the control mechanism, and which can be manufactured and serviced at a relatively low cost.

Further objects relate to features of construction and will be apparent from a consideration of the following description and the accompanying drawings wherein:

Fig. 1 is a side elevation of a self-propelled wheel chair constructed in accordance with the present invention;

Fig. 2 is a top plan view of the wheel chair shown in Fig. 1;

Fig. 3 is a section on the line 3 3 of Fig. 1; and Figs. 4 and 5 are views showing schematically the control system.

In accordance with the present invention I provide a self-propelled wheel chair or the like conveyance which comprises a chassis having at or adjacent to one end a pair of fixed driving wheels and at or adjacent to its opposite end one or a pair of swivelly mounted wheels, each of the driving wheels having diseng-ageable clutches which may be of conventional design. The clutches have a driving connection with a suitable electric motor operated by a battery which may be charged by being plugged into the circuit, thus permitting the use of the conveyance indoors without the discharge of obnoxious fumes. The swinging movement'of the swivelly mounted wheel or wheels is controlled by cooperating latches or other suitable means normally operative to hold the wheels in position, but disengageable so as to permit swinging movement Awhen making a turn.

The control system for operating the motor, clutches t.

and latches may be mechanical, pneumatic, hydraulic vand/ or electrical, but in any case it comprises an operating lever or control means, such as a handle, conveniently individual so as to be selectively moved from a neutral position, wherein the motor is disengaged or turned off and both clutches are engaged so as to hold the swivel wheels, to one of three forward positions, viz., a first `position wherein the motor is turned on with both clutches engaged and the latches operative to hold the swivelly mounted wheel or wheels in position to drive the conveyance straight-ahead, to a second position, wherein the motor is turned on with one of the clutches disengaged and the latches positioned to permit a smooth turning of the conveyance in one direction, and to a third position, wherein on with the other clutch disengaged and the latches positioned to permit turning the conveyance in the oppomotor, preferably an conventional lighting the motor is turned flll straight-ahead f site direction. lf desired, the operating lever may also be selectively moved to one of three backward positions corresponding to the forward postions so that the conveyance may be driven forwardly and backwardly and turned right or left. Although a separate braking system may be employed, it is preferably interconnected with the control system so that the brakes are automatically applied when the operating lever is moved to neutral position.

By referring to the drawings which show what is now considered a preferred embodiment of the invention, the numeral 1 designates a chassis having spaced side frame plates 2 and 3 rigidly connected by cross rods or members 4, 5 and 6, and a shelf-like horizontal plate 8 which provides a support for parts hereinafter described. The front ends of the plates 2 and 3 are formed with `aligned openings which receive bearings for the fixed driving wheels 8 and 1d, the peripheries of which carry tires formed with double staggered rows of heavy bosses 11 and 12 between which are annular grooves for receiving a driving belt.

The rear of the side plates below the shaft 8 carry brackets and king pins 14 and 15 on which the rear wheels 16 and 17 are swivelly mounted. The king pins are interconnected by the usual linkages 2t), 21 and 22 by means of which the wheels 16 and 17 swing together at the proper angle. A fixed collar 24 (Fig. 3) is carried at the center of link 22 and the opposite faces of the collar are engaged by latches 25 and 26 mounted on rockers 25a and 26a carried by shafts 28 and 3i) which are journaled in bearings 32 and 34 fixed to the underside of shelf plate 3. lt will be noted that when the latch 25 is released or disengaged, the link 22 may be moved to the left (Fig. 3), thus permitting the wheels 16 and 17 to swing in one direction; that when the latch 26 is released or disengaged the link 22 may be moved to the right, thereby permitting the wheels 16 and 17 to swing in the opposite direction; and in either case when the link 22 is restored to neutral or straight ahead position, both latches engaged the collar 24 to hold the parts in this position.

The rear ends of the side frame plates are formed with integral upwardly curved projections which extend from below the axes of wheels 16 and 17 so as to provide curb skids 36 and 3S permitting the conveyance to ride over curbings, low steps and uneven terrain without subjecting the occupant to objectionably severe shocks. Mounted in suitable bearings carried by side frame plates 2 and 3, and below the inner part of shelf 8, is a shaft 40, the ends of which project outwardly beyond the side frame plates. The end portions of shaft 411 carry clutch-driving pulley assemblies 41 and 42, comprising conventional friction clutches having their shifting forks or rods mounted on rocker shafts 28 and 3@ so that when either one of the latter is rocked to release the associated latch the associated clutch is disengaged at the same time. The driven clutch plates are mounted on the inner ends of sleeves rotatable on the end portions of shaft 40 and the outer ends of these sleeves carry pulleys 44 and 45 aligned with the grooves between the treads 11 and 12 of the drive wheels. Between the pulleys 44, 4S and the side frame plates are rollers 46 and 47 having diameters somewhat greater than those of pulleys 44 and 4S, the purpose of which is hereinafter pointed out. Drive belts 56 and 51 pass about the drive pulleys 44, 4S' and drive wheels 8, 10, and adjustable belt tighteners 54 and 55, carried by brackets fixed to the side frame plates, are provided to maintain the proper tension on the belts.

A sprocket 60 (Fig. 2), fixed to shaft dit, is driven by a chain 61 which is connected to a sprocket fixed to the output shaft of a worm gear reduction mechanism 64 mounted on the shelf 8. The input shaft of the reducer 64 is connected by belt 65 to an electric motor 66 which .3 is also mounted on shelf 8. The electric motor 66 is connected through a control system hereinafter described with a storage battery 68 mounted on a U-shaped bracket 70 pivoted at 71 to the side frame plates 2 and 3.

Forwardly of the battery bracket 70 is the occupants seat assembly 72 comprising a seat section 74, back rest 75, side member 76 the upper parts of which are bent outwardly to form arm rests 77, and foot rest 78 which are pivoted to the lower parts of the side members. The seat assembly 72 is pivotally supported at 80 to the side frame plates and links 82 connect the central parts of the side members 76 with the sides of battery bracket 70 to provide, in effect, a pair of four-bar linkage system which maintains the seat section 74 and battery support horizontal at all times.

The operation of the conveyance is controlled by a system comprising solenoids S4 and 86 having push rods 85 and 87, connected with their respective armatures. The solenoid 84 is mounted on a bracket 96 secured to the side frame 2 so that the lower end of its push rod 85 is contiguous to the tail of the rocker 25a which carries the latch 25. Likewise solenoid 86 is mounted on a bracket 92 secured to side frame 3 with the lower end of its push rod 87 contiguous to the tail of rocker 26a which carries latch 26.

The solenoids 84, 86 and motor 66 are connected in an electric circuit housed with control box 94 and controlled by the operation of a bar or rod 95 (Figs. 1 and 4) which is rotatable and slidable axially in bearings 96 and 98 secured to the underside of one of the arm rests 77. The control rod is moved from neutral position to any of the siX operating positions by handle 100 carried by its outer end and projecting upwardly through an opening 102 in the arm rest, the opening 102 being in the form of two opposed triangles which define the neutral position n, where the apices of the triangular openings join each other, three forward positions a, b and c, and the three backward positions x, y and z. Compression springs 104 and 105 (Fig. 1), circumposed about the rod 95, act against a centrally disposed collar 106 carried by rod 95 and the bearing members 96 and 98, so as to return the control rod to and normally maintain it in neutral position.

The control system shown in Figs. 4 and 5 comprises tive rotary contacts 111-15 mounted on the control rod 95 in axially spaced relation. The contact 111 is formed with end recesses 116 and 117 and an intermediate recess 118, and the contact is formed with an intermediate recess 119. Fixed contacts or brushes 121-125 are so disposed with respect to the contact 111 that axial movement of the control rod 95 to position a brings the contact into engagement with contact 111 and rotary movement of the control rod 95 to position b brings contact 123 into engagement with contact 111, and rotary movement to position c brings contact 121 into engagement with contact 111; and when the control rod is shifted to position x, y and z, the contact 111 is brought into corresponding engagement with contacts 125, 124 and 122. The iixed contact 126 remains at all times in engagement with contact 111 regardless of the position of control rod 95 and ixed contacts 128 and 130 likewise remain in engagement with contacts 112 and 155, respectively, regardless of the position of control rod 95. Fixed contacts 131 and 132 are so positioned with respect to contacts 112-114 that movement of control rod 95 to positions a, b or z: brings contacts 113 and 114 into engagement with contacts 131 and 132, respectively; and movement of control rod 95 to positions x, y or z brings contacts 112 and 113 into engagement with contacts 131 and 132, respectively. A tixed contact 134 is so positioned with respect to the recess 119 that axial movement of control rod 95 in either direction brings the contacts 134 and 115 into engagement.

Contacts 125 and 126 are connected in a circuit 135 which connects one terminal of battery 68 with one terlift minal of the armature 137 of motor 66, the other terminal of the armature being connected by circuit 138 with contact 128. The terminals of the motor eld 140 are connected with contacts 131 and 132 by lines 141 and 142, respectively, and the other terminal of the battery 136 is connected to contact 134 by circuit 144. Contacts 121 and 122 are connected in parallel in circuit 145 leading to one terminal of solenoid 84, and likewise contacts 123 and 124 are connected in circuit 146 leading to one terminal of solenoid 86. The other terminals of solenoids 84 and 86 are connected with circuit 148 leading to contact 130. The contacts 112, 114 and 115 are at times interconnected by circuit 150.

Movement of the control rod 95 to position a not only closes circuit but also interconnects it with circuits 138, 141, 142, 150 and 144, thus causing the motor 66 to rotate in forward direction; and movement of control rod 95 to position x reverses the ow of current through tield thereby causing the motor 66 to rotate in the opposite direction, it being noted that in either position the circuits and 146 to solenoids 84 and 86 remain open. When the control rod 95 is moved to positions b or y the circuits 135, 146 and 148 are interconnected so as to energize solenoid 86 which operates theV clutch 42 and latch 26; and likewise when the control rod 95 is moved to position c or z the circuits 135, 145 and 148 are interconnected so as to energize solenoid 84 which operates clutch 41 and latch 25.

A summary of the operation of the conveyance is as follows: v

With the operator in the seat 74 and the handle 100 in neutral position, the clutches 41 and 42 are engaged and the latches 25 and 26 hold the swivel wheels 16 and 17 locked in straight-ahead position, the transmission mechanism being elective to act as a brake preventing rotation of the drive wheels. When the operating handle is moved straight forward to the rst position (a), the motor is turned on with the clutches 41 and 42 engaged and the latches 25 and 26 holding the wheels 16 and 17 in straight-ahead position, since the circuits to solenoids 84 and 86 remain open, whereupon the conveyance travels straight ahead. When the handle 100 is moved to the second position (b), the motor is or remains turned on, but the circuit to solenoid 86 is closed, thereby causing push rod 87 to move downwardly to depress the tail of the rocker 26a whereupon the latch 26 becomes disengaged from collar 24 and as shaft 30 is rocked, the clutch 42 is disengaged, thereby interrupting the driving connection to the drive wheel 10, whereupon the drive wheel 8 is eiective to swing the conveyance to the right and at the same time the swivelly mounted wheels 16 and 17 have been released so that they may swing counter-clockwise (Fig. 2), thus permitting a smooth sharp turn. When the handle 100 is moved to the third position (c), the motor is or remains turned on, but the circuit to solenoid 84 is closed thereby causing push rod 87 to depress the tail of rocker 25a, whereupon the latch 25 becomes disengaged from collar 24 and as shaft 28 is rocked, clutch 41 becomes disengaged, thereby'interrupting the driving connection to drive wheel 8, whereupon the drive wheel 10 is eective to swing the conveyance to the left and at the same time the latch 25 releases the wheels 16 and 17 so that they may swing clockwise, thus permitting a smooth sharp left turn.

When the operating handle 100 is moved rearwardly to position x, the motor is turned on but its direction of rotation is reversed, and as the clutches and latches remain engaged (as in position a), the conveyance moves straight backward. When the handle 100 is moved to position y, the motor remains on, but the circuit to solenoid 86 is closed (as in position b), thereby causing the drive wheel 8 to swing the conveyance to the right and at the same time the wheels 16 and 17 are allowed to swing counter-clockwise (Fig. 2), thus permitting a smooth right backward turn. When the handle is moved to posi- 5 tion z, the motor remains on, but the 84 is closed (as in position c), thereby causing the drive wheel 100 to swing the conveyance to the left and at the same time the wheels 16 and 17 are allowed to swing clockwise (Fig. 2), thus permitting a smooth left backward turn.

In traveling forwardly over uneven terrain the belts 50 and 51 circuit to solenoid 82 is such as to minimize, if not prevent objectionable swing, since the weight of battery and its support, together with the weight of the occupant, act as cooperating dampening devices.

disclosure is for the purpose of illustration, and that various changes and modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

We claim:

which is operative to lock said swivelly mounted wheel against swinging in the opposite direction, and a control system including an operating lever interconnected with said motor, clutches and latches, said lever being selectively movable from a neutral position, wherein the motor is turned off and both clutches are engaged to a rst position, wherein said motor is turned on with both clutches the other of said clutches and the disengaged so as to turn the wheel direction.

2. A self-propelled wheel chair comprising a chassis having at one end fixed driving wheels and at its opposite end a swivelly mounted wheel, each driving wheel having a grooved periphery, a pair of driving pulleys interposed between said driving wheels and swivelly mounted wheel peripheral grooves of said driving the lower part of each driving pulley being spaced from a plane tangent to the bearing surfaces of said driving wheels and swivelly mounted wheel, a belt extending about each of said driving pulleys and the grooved periphery of the aligned driving wheel so as to provide a driving connection for said driving wheels and traction belt engageable with projecting terrain over which the wheel chair travels, a clutch for each driving pulley, a motor other of said latches chair in the opposite having a driving connection with each clutch, steering adjuncts including cooperating latches, one of which is operative to lock said swivelly mounted wheel against swing- 3. A wheel chair as rearward positions corresponding to the three forward positions.

4. A self-propelled wheel chair comprising a chassis having at its front end a pair of caged, is turned on with said clutches and locking means engaged, to a second position, wherein said motor is turned engaged and said locking wheel chair to turn in one and to a third position, wherein said motor is turned on with the other of said clutches disengaged and said locking means disengaged to permit the wheel chair to turn in the opposite position.

5. A self-propelled wheel chair as set forth in claim 4, wherein said control lever may be selectively moved to one of three backward driving positions corresponding to the forward driving positions.

motor having driving connections with said drive wheels, frame members having vertically extending sides pivotally connected adjacent to their upso as to provide four-bar linkage systems maintaining with said drive shaft, drive pulleys carried by the end pulleys, the diameter of said rollers being greater than that of said drive pulleys, and belts extending about said drive pulleys and peripheral grooves of said drive wheels, said belts driving said drive wheels and providing traction means when said wheel chair passes over terrain having projections engageable with said belts, and said rollers being engageable with such projections to elevate the rear of said wheel chair to permit said swivelly mounted wheels to ride thereon without objectionable shock.

8. A self-propelled wheel chair comprising a chassis having at its front end a pair of relatively large driving wheels and at its rear a pair of relatively small swivelly mounted wheels, locking means for holding said swivelly mounted wheels in straight-ahead position, a clutch connected to each driving wheel, an electric motor having a driving connection with each clutch, solenoids having plungers operatively connected with said clutches and locking means, and a control system comprising an operating member axially movable and rotatable, electrical contacts selectively operated by said members in response to movements thereof, and connections between said contacts, motor and solenoids effective when said member is moved axially to turn on said motor, when moved axially and rotated in one direction to turn on said motor and operate one of said solenoids so as to release one of the clutches and locking means, thereby to cause the wheel chair to turn in one direction, and when moved axially and rotated in the opposite direction to turn on said motor and operate the other solenoid so as to release the other clutch and locking means, thereby to cause the wheel chair to turn 1n the opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS 995,291 Robinson June 13, 1911 1,020,707 Lemp Mar. 19, 1912 2,426,342 Couse Aug. 26, 1947 2,454,070 Le Tourneau Nov. 16, 1948 2,544,831 Guyton Mar. 13, 1951 FOREIGN PATENTS 295,513 Italy Apr. 23, 1932 810,859 Germany Aug, 13, 1951 

